In the case of a hearing aid, an input signal is received by means of an input converter and converted into an electrical input signal. Normally, at least one microphone which receives an acoustic input signal serves as the input converter. Modern hearing aids frequently comprise a microphone system having a plurality of microphones in order to achieve a reception which is dependent on the angle of incidence of acoustic signals, a directional characteristic. The input converters can however also include a telephone coil or an antenna for receiving electromagnetic input signals. The input signals converted into electrical input signals by the input converter are delivered to a signal processing unit for further processing and amplification. The further processing and amplification takes place in order to compensate for the individual hearing loss of a hearing aid wearer, depending on the signal frequency as a rule. The signal processing unit provides an electrical output signal which is delivered by way of an output converter to the ear of the hearing aid wearer, such that the latter perceives the output signal as an acoustic signal. Earpieces which generate an acoustic output signal are normally used as the output converter. However, output converters for generating mechanical oscillations are also known which directly excite certain parts of the ear, such as the auditory ossicles for example, to cause them to oscillate. Furthermore, output converters are known which directly stimulate nerve cells of the ear.
With regard to hearing aids, parameters affecting the signal processing can usually be set by the hearing aid wearer. One parameter of this type is for example the volume setting. In the case of modern hearing aids, the selected values for the relevant parameters are normally stored in digital form in a memory. In this situation, the setting is made by the user either by using control elements situated directly on the hearing aid or by means of a remote control facility for the hearing aid in question. In addition, parameters can also be selected automatically as a result of a signal analysis, for example as a result of analyzing the acoustic input signal in order to determine the hearing situation in which the hearing aid presently finds itself. Such types of hearing situations are for example “quiet environment”, “conversation in background noise”, “journey in car”, etc.
The central constructional element of the signal processing unit of a modern hearing aid is a digital signal processor (DSP). This can be implemented in a freely programmable, hardwired or hybrid form. The values of selectable parameters which influence the signal processing must first be read from the memory after turning on and transferred into the digital signal processor.
During the customization of a hearing aid to the individual hearing loss of a hearing aid wearer, default settings for the parameters which can be set by the hearing aid wearer are also defined in addition to parameters which the hearing aid wearer is no longer able to change during normal operation of the hearing aid. Also defined is the hearing program in which the hearing aid is operated as standard after being turned on. The default settings defined once in this manner for the respective hearing aid wearer are then set automatically each time after the hearing aid is turned on, in other words read out from a non-volatile memory and transferred into the digital signal processor.
One of the most frequent problems for hearing aid wearers is an incorrect volume setting of the hearing aid for their specific everyday hearing situations. The main reason for this is the fact that the hearing aid is adjusted by the acoustician in artificial hearing situations which generally differ in respect of sound types and levels from the relevant individual hearing situations. This can be corrected by means of volume controls which can be arranged directly on the hearing aid or a remote control facility. However, in the case of digital hearing aids having continuous controls for setting the parameter or parameters the corrected settings lose their current value after the hearing aid is turned off, and when the hearing aid is turned on again are set to the initial value selected during the customization process. If this latter value differs from the preferred value, then it must be adjusted. This requires a further visit to the acoustician and is therefore bothersome for the hearing aid wearer. In addition, the latter must take note of the corresponding correction settings, which is problematical, particularly in the situation when in the case of a hearing aid having a plurality of hearing programs different settings for a particular parameter are offered in different hearing programs in order to customize the signal processing to different hearing situations.
A programmable hearing aid is known from patent specification U.S. Pat. No. 5,604,812, which can be automatically adapted to different hearing environments. For continuous, automatic and autonomous adaptation of its transmission characteristics, the hearing aid includes in addition to a microphone, earphone and amplifier/transmission circuit, a first data memory in which audiometric data is stored, a second data memory in which hearing aid characteristics are stored, a third data memory in which algorithms are stored, a signal analysis unit that determines control signals dependent on input quantities characteristic of the current ambient situation, and also includes a data processing unit, the data processing unit offering hearing aid setting data for the amplifier/transmission circuit from the data of the data memories and from the control signals of the signal analysis unit, so that the transmission characteristics of the amplifier/transmission circuit can be automatically determined from the edited audiometric data, hearing aid characteristics, prescribable algorithms and the input quantities characteristic of the current ambient situation.
A hearing aid with the facility for data recording is known from the publication EP 0 335 542 A2. The recorded data comprises information relating to the frequency with which a switchover between individual hearing programs occurs, and the period of time for which the individual hearing programs are switched to active. The recorded data is read out by a hearing aid acoustician, evaluated and used for renewing settings for the hearing programs.
A method for selecting a suitable hearing program in the case of a multi-program hearing aid is known from the publication WO 2004/056154 A2. In this situation, the selection of a suitable hearing program can also take place by taking account of manual user inputs. For example, the volume setting associated with a hearing program is incremented by one dB each time the user manually increments the volume by any value during operation of this hearing program.
A programmable hearing aid with trainable automatic adaptation to different hearing situations is disclosed in publication US 2005/0129262 A1. In this situation, an automatic customization of the parameter sets available for different hearing situations can take place in a particular mode of operation. The customization takes place depending on the frequency of the changes made manually by a user for a particular parameter.